Molar Mass Calculator

Grams per mole from measured mass and amount.

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Formula

MM = mass ÷ n

Molar mass links macroscopic grams to moles. For a pure compound, MM equals formula weight from the periodic table.

Worked example

58.44 g of NaCl for 1 mol gives MM = 58.44 g/mol.

Where this can give the wrong answer

  • Moles must be positive.
  • Impure samples inflate apparent molar mass.
  • Polymers and mixtures do not have a single MM.

FAQ

Numerically the same in g/mol for a molecule; molar mass is the IUPAC term.